Portable media player with adaptive playback buffer control

ABSTRACT

The invention relates to a portable content presentation device ( 101 ) such as a portable audio player. The portable presentation device ( 101 ) comprises a content signal source ( 103 ) for providing a first content signal. A memory ( 111 ) buffers content signal to provide electronic shock protection. The portable presentation device ( 101 ) comprises a presentation signal generator ( 105 ) which generates a suitable presentation signal. The portable presentation device ( 101 ) also comprises a memory controller ( 113 ) which dynamically adjusts the buffer memory allocation and creates a second memory allocation of the memory ( 111 ) for a second application. A portability processor ( 123 ) determines a portability state, e.g. indicating stationary or portable use, and the memory allocation is in response thereto, such that the buffer memory is reallocated to the second application, when the portable presentation device ( 101 ) is used in a stationary mode. The second application may be a second presentation application such as a presentation application for images.

The invention relates to a portable content presentation device andmethod of presenting content therefor and in particular to a portableaudio player capable of performing a second application.

In recent years, the quantity and variety of consumer electronicproducts have increased dramatically. To a large extent this increasehas been associated with increased availability and use of digitalsource encoding and distribution for a number of different content typesthat were previously encoded and distributed in analogue form. Thesecontent types include audio signals and video signals.

For example, video signals and TV broadcasts are traditionallytransmitted as analogue signals. However, digital encoding isincreasingly used and specifically TV broadcasts using digital MPEG 2encoding are gradually becoming more prevalent than analoguetransmission. Likewise, audio signals are typically encoded in analogueform for radio broadcasts but in the last decade digital radio broadcasttransmissions have been made available, for example through thestandardisation of a broadcast standard such as the Digital AudioBroadcast (DAB) standard.

In the field of storage media based audio content distribution, digitalsource encoding and distribution has become commonplace over the lastcouple of decades. A well-known example is the Compact Disc (CD), whereaudio signals are stored as digital sample values of the original audiosignal. In latter years, this trend has continued by a number of digitalcompression techniques being developed to allow for reduced storage anddistribution bandwidth requirements. An example is the well-knowncompression standard MP3, which significantly reduces the required datasize for encoding an audio signal in comparison to for example CDs.

In another field, digital photo cameras have become generally availableand are close to achieving higher sales numbers than conventional filmbased cameras. This has resulted in new devices being developed capableof storing, processing and displaying digital pictures.

The advent of many different digitally encoded signals has resulted in aconvergence of devices and applications associated with differentcontent signals. For example, storage media such as recordable CDs ormemory cards may be used with many different content signals includingfor example digitally encoded music or digital pictures. Furthermore,there is currently a trend towards merging different functionality intosingle devices. In addition, there is a trend towards increasingfunctionality and capabilities of portable devices. This trend is to alarge extent driven by the opportunities provided by the digitalrepresentation of content signals and the therewith associated digitalprocessing.

For example, traditionally portable music players such as CD playerstypically comprise a small built in display for providing informationand facilitating navigation. However, devices are emerging which arecapable of both audio and video content presentation. In this case thevideo display unit may additionally be used for information andnavigation of the audio content. The video display unit may for examplebe an external TV.

For example, many portable CD players are currently capable of decodingMP3 encoded audio signals. As another example, most digital camerasprovide video recording facilities and most digital camcorders providesome digital photography function. As a third example, many mobilephones provide the additional capability of decoding and playing MP3encoded signals.

However, typically, the combination of different and possiblyincompatible functions increases the requirements of a device andespecially increases the computational and memory requirements. Hence,additional processing power and memory must typically be includedthereby substantially increasing the cost of the device. Especially, forcontent presentation devices, the additional memory resources aretypically very substantial and have a significant associated costimpact.

Hence, an improved content presentation system would be advantageous andin particular an improved content presentation system which allows foran improved performance of applications and/or improved memoryefficiency would be advantageous.

Accordingly, the Invention seeks to mitigate, alleviate or eliminate oneor more of the above mentioned disadvantages singly or in anycombination.

According to a first aspect of the invention, there is provided aportable content presentation device comprising: a content signal sourcefor providing a first content signal; a memory; a presentation signalgenerator operable to generate a presentation signal from the firstcontent signal; a portability processor for determining a portabilitystate of the portable content presentation device; and a memorycontroller operable to dynamically adjust a first memory allocation ofthe memory associated with the first content signal and to create asecond memory allocation of the memory for a second application inresponse to the portability state.

The content presentation device may for example be a portable CD player,DVD player, MP3 player or digital radio. The presentation signal may forexample be an audio signal or a visual signal. The content signal sourcemay be an internal content source such as a CD drive or may be interfacemeans operable to receive a content signal from an external source. Thememory controller may for example adjust the first memory allocation andcreate the second memory allocation by dividing the available memoryinto a first memory allocation and a second memory allocation. A givenmemory partition may for example be allocated as a buffer memoryallocation or as a second memory allocation in response to a givencharacteristic or occurrence. Specifically, the memory controller mayswitch between allocating the entire memory as the first memoryallocation or as the second memory allocation. Alternatively, the memorymay be partitioned efficiently between concurrent applications.

Accordingly, the invention allows for an improved portable contentpresentation device, which has an improved memory efficiency. Inparticular, memory associated with the first content signal may bereused as memory for a second application. Hence, the performance of thesecond application may for example be improved or enabled by this memoryallocation. The total memory requirement of a portable contentpresentation device capable of performing a second application may bereduced. Especially a content presentation device having multiplefunctions and capabilities thus benefits from an improved dynamic memoryallocation. Available memory may specifically be shared or allocatedaccording to current requirements and needs. Increasing memoryavailability may typically increase speed of processing. Thus, theinvention tends to provide a content presentation device having improvedmemory efficiency, reduced cost, increased flexibility, reducedcomplexity and or increased processing speed.

Specifically, the requirement for memory associated with the firstcontent signal, for example buffer memory, may often be associated withthe current portability characteristics of the portable presentationdevice and by allocating buffer memory in response to a portabilitystate an improved memory allocation can be achieved. Specifically, thebuffer memory allocation may be determined so as to achieve acceptableperformance for the current portability state, and specifically thebuffer memory allocation may increase for increasing movement. In thiscase, the second memory allocation will tend to be maximised while theimpact on the performance is negligible. The portability state may forexample be determined from a user input.

According to a feature of the invention, the first memory allocation isa buffer memory allocation for the first content signal. This allows forbuffering in a portable state while allowing the memory to be reusedwhen buffering is not needed in a stationary state.

According to another feature of the invention, the first memoryallocation is electronic shock protection memory, and the portablecontent presentation device comprises a shock protection processoroperable to control the buffering of the first content signal in thememory so as to reduce fluctuations in a content signal buffer outputrate. Hence, the invention allows for the electronic shock protectionmemory of a portable device to be used by a second application. This mayimprove the performance of the application. Specifically, the completememory, or a part of it, may be allocated to the second application whenno or less shock protection memory is necessary for acceptableperformance of the content presentation of the content signal. Hence,the performance of the portable presentation device may be improved.Alternatively or additionally, the memory requirements of the portablepresentation device may be reduced thus resulting in lower cost.

According to another feature of the invention, the portability statecomprises a portability state indication of whether the portable contentpresentation device is in a substantially stationary state or in asubstantially portable state. This allows for a simple and reliableportability state detection while ensuring advantageous memoryallocation and good performance. The buffer memory requirements aretypically low or non-existent for a stationary use but high for anon-stationary use. For example, for electronic shock protection memory,substantially all of the memory may typically be allocated to the secondmemory allocation for stationary use. However, for non stationary use,substantially all of the memory may be allocated for the buffer memoryallocation.

According to another feature of the invention, the portability processoris operable to set the portability state indication in response to amovement detection. The movement detection may be a direct detection,for example by a dedicated movement detector, or may be indirect, forexample through the detection of interruptions in the content signalfrom the content signal source. This feature allows for a suitable andadvantageous implementation for detection of a portability stateindication.

According to another feature of the invention, the portability processoris operable to set the portability state indication in response to adetection of the portable content presentation device having an externalconnection. An external connection may for example be a connection toexternal presentation means. The detection of a connection may be bydetection of a signal, characteristic or indication associated with anexternal device. Alternatively or additionally, the detection may be bya physical detection for example by detecting that a connector has beenattached to the portable presentation device. A very reliable, simpleand easy to implement means of determining a portability stateindication may thus be provided.

According to another feature of the invention, the external connectionis an external connection to a substantially stationary presentationdevice. Depending on the content signal and/or the second application,the device may for example be an external monitor such a as a TV, anaudio amplifier such as a HiFi device or a computer. An externalconnection to a substantially stationary presentation device provides ahigh likelihood of the portable presentation device being used in astationary mode and thus the portability state indication may be setwith high reliability.

According to another feature of the invention, the external connectionis an external connection to a power source. An external power sourcemay for example be detected by the external power being available or bya power connector being connected to the portable presentation device.The presence of an external power source provides a high probability ofthe portable presentation device being used in a stationary mode, andthus the portability state indication may be set with high reliability.

According to another feature of the invention, the second application isa control application of the portable content presentation device. Thecontrol application may for example be a user interface application suchas a graphical user interface (GUI). The control application mayspecifically be associated with stationary operation such as anapplication predominantly used in stationary mode. For example, a GUImay only be provided when the portable presentation device is connectedto an external monitor. Hence, the control application may be enabled orimproved performance may be enabled by an allocation of buffer memory tothe control application.

According to another feature of the invention, the content signal sourceis further operable to provide a second content signal and the secondapplication is a processing function associated with the second contentsignal. Preferably, the second application is a presentation applicationof a second content signal. The portable presentation device may becapable of presenting different types of content signals. For examplethe portable presentation device may be capable of presenting an audiosignal, such as an MP3 signal, as well as a simultaneous presentation ofvisual data, such as digital pictures. The content signal source maycomprise a plurality of different sub content sources such as forexample a memory card and a CD drive. Different functionality may thusbe merged in the portable presentation device, and the available memorymay be allocated dynamically between these. Specifically, theperformance of the content presentation of the second application may beimproved if the buffer memory is not required for the presentation ofthe content signal from the content signal source.

According to another feature of the invention, the second content signalis a different type of content signal than the first content signal.Preferably, the first content signal is an audio content signal and thesecond content signal is a visual content signal. The memory may be usedto optimise the performance of presentation applications for differenttypes of content signals.

According to another feature of the invention, the second application isan image presentation application and the portable content presentationdevice is operable to use the second memory allocation as an imagecache. The use of the memory for both buffer memory and as an imagecache may increase performance and/or reduce memory requirements asdifferent benefits for the different content signals can be obtainedfrom the same memory.

According to another feature of the invention, the second application isenabled by the creation of the second memory allocation. Specifically,the second application may be an application which is only availablewhen the portable presentation device is stationary. This allows foradditional applications to be provided without increasing memoryrequirements, as the applications are only provided when the memory isavailable.

According to another feature of the invention, the memory consists in asingle memory element. This may allow for reduced cost and size of theportable presentation device as single memory elements tend to becheaper and take up less space.

According to a second aspect of the invention, there is provided amethod of presenting content, the method comprising: receiving a firstcontent signal; buffering the first content signal in a memory;generating a presentation signal from the first content signal; anddynamically adjusting a buffer memory allocation of the memory forbuffering of the content signal and a second memory allocation of thememory for a second application.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiment(s) described hereinafter.

An embodiment of the invention will be described, by way of exampleonly, with reference to the drawings, in which

FIG. 1 is an illustration of a portable audio player in accordance withan embodiment of the invention; and

FIG. 2 is an illustration of a flowchart of a method of presentingcontent in accordance with an embodiment of the invention.

The following description focuses on an embodiment of the inventionapplicable to a portable audio player and in particular to a portableaudio player additionally capable of presenting a second visual contenttype such as digital images. However, it will be appreciated that theinvention is not limited to this application. The specific embodimentwill focus on an embodiment wherein the first memory allocation isbuffer memory and specifically electronic shock protection memory.However, it is within the contemplation of the invention that the firstmemory allocation may be used for any suitable application associatedwith the first content signal.

FIG. 1 is an illustration of a portable presentation device inaccordance with an embodiment of the invention. In the describedembodiment, the portable presentation device is a portable audio player101 capable of playing an audio signal.

The portable audio player 101 comprises a content signal source 103which in the preferred embodiment is a CD drive capable of retrievingdata stored on a compact disc.

The content signal source 103 provides a data stream corresponding tothe data read from the CD. The content signal may in the preferredembodiment typically be a normally PCM (Pulse Code Modulation) encodedsignal, or may be an MP3 encoded signal, dependent on the CD that hasbeen loaded in the portable audio player 101.

The content signal source 103 is connected to a presentation signalgenerator 105 which generates a presentation signal from the contentsignal received from the content signal source 103. In the preferredembodiment, the presentation signal generator 105 decodes the contentsignal and generates an analogue audio signal as is well-known in theart. Depending on the nature of the content signal the decoding may forexample include PCM decoding or MP3 decoding.

The presentation signal generator 105 is connected to a first outputelement 107 which can be connected to a first external presentationdevice 109. In the preferred embodiment, the first output element 107 isan analogue audio amplifier which amplifies the analogue audio signalgenerated by the presentation signal generator 105 to a suitable levelfor the first external presentation device 109. The first externalpresentation device may specifically be headphones, speakers or anexternal amplifier or audio processing equipment.

The content signal source 103 is furthermore coupled to a memory 111.During operation, the content signal from the content signal source 103may be fed to the memory 111 and buffered therein. In the preferredembodiment, the memory is capable of functioning as a FIFO (First InFirst Out) buffer wherein the data stream from the content signal source103 is temporarily stored. An advantage of a FIFO buffer is thatvariations in the incoming data rate can be compensated, and the datacan be read out at a substantially constant rate. Hence, the memory mayfunction as electronic shock protection memory. In use, a portable CDdrive tends to be susceptible to physical movement and shocks such thatthe content signal may be temporarily interrupted. Hence, the contentsignal from the content signal source 103 may exhibit significantvariations which cause audible interruptions if not compensated.However, by buffering the signal in the memory 111, data can be readsubstantially continuously, and thereby interruptions in the audiooutput can be reduced. The larger the buffer memory the higherprotection against shocks is achieved. In the embodiment of FIG. 1, thepresentation signal generator 105 may receive the content signaldirectly from the content signal source 103 or via the memory buffer ofthe memory 111.

The portable audio player is furthermore capable of performing otherapplications than just playing the audio signal. In differentembodiments, the portable audio player may for example be capable ofpresenting a video signal received from an external source, presenting agraphical user interface or performing source signal encoding functions.Accordingly, the portable audio player 101 comprises a memory controller113 which is operable to allocate the memory 111 (or parts thereof) todifferent applications. Specifically, the memory controller 113 candynamically adjust a first memory allocation of the memory 111 forbuffering of the content signal whereby a second memory allocation maybe created that can be used for the second application. In the preferredembodiment, the first memory allocation is a buffer memory allocation.Hence, the memory controller 113 can control the allocation of thememory 111 between the second application and the buffering of thecontent signal from the content signal source 103. The buffering andthus the shock protection may for example be traded off against theperformance and memory requirements of the second application.

In the preferred embodiment, the second application is a second contentpresentation of a second content signal. The second content signal maybe of a different type than the first content signal, and is in thepreferred embodiment a content signal comprising digital images.

Accordingly, the portable audio player 101 of FIG. 2 further comprises asecond content signal source 115. The second content signal source 115may for example be a memory card comprising digital pictures from adigital camera. In some embodiments, the first and second content signalsource 113, 115 may be the same content signal source. For example theCD drive of the first content signal source 113 may additionally be usedto retrieve digital images stored on a CD such as for example a photodisc produced during development of conventional film based pictures.

The second content signal source 115 is connected to a secondpresentation signal generator 117, which generates a second presentationsignal. In the preferred embodiment, the second presentation signalgenerator 117 generates a video signal comprising one or more of theimages received from the second content signal source. Specifically, thesecond presentation signal generator 117 is operable to change the imagecontents of the video signal. In particular, the second presentationsignal generator 117 may receive user inputs and select a specific imagefrom the second content signal to be presented accordingly. The secondpresentation signal generator 117 is thus preferably operable to accessthe second content signal source 115 to retrieve the required contentdata.

The second presentation signal generator 117 is connected to a secondoutput element 119 which is operable to interface the secondpresentation signal to a second presentation device 121. In thepreferred embodiment, the second presentation device 121 is a videomonitor or TV, and the second output element 119 is operable to amplifyand modulate the video signal from the second presentation signalgenerator 117 such that it is suitable for the video monitor or TV.

Hence, in the preferred embodiment, the portable audio player 101additionally provides a second application that enables a user to viewdigital images on a TV or video monitor. The user may select whichpicture to view, navigate through pictures, present a slide show andmanipulate pictures. In the preferred embodiment, the differentapplications may further co-exist and be integrated with each other.Thus, for example, an MP3 encoded music sequence may be associated witha specific image, and when this image is selected, the associated musicsequence may be played. The first and second presentation device 109,121 may thus specifically be the same device.

The second content signal source 115 is furthermore connected to thememory 111, and in the preferred embodiment, the memory controller 113is operable to control the memory 111 such that memory is allocatedbetween the two applications according to a given algorithm.Specifically, the memory 111 is in the preferred embodiment used as animage cache for the second application. Hence, the memory 111 allocatedto the second application enables a faster access to the images and thusa faster performance. The performance of the second application thustends to improve for increased memory allocation sizes.

In the preferred embodiment, the second application furthermorecomprises presenting a Graphical User Interface (GUI) to a user. Hence,the second presentation signal generator 117 is additionally operable togenerate a GUI signal for presentation on the second presentation device121. The GUI may specifically be used to control the presentation ofimages. The GUI application may further use memory allocated to thesecond application.

In some embodiments, the second application may be a differentrepresentation of the first signal source, such as a GUI, an index of(audio) content, visual effects etc.

In the preferred embodiment, the memory allocation of the memory 111 ofthe portable audio player 101 is allocated in response to a portabilitystate of the portable audio player 101. For example, in the preferredembodiment the requirement for electronic shock protection is highestwhen the portable audio player 101 is used as a portable device.However, the second application of image presentation is associated withan external and typically stationary presentation device 121, andtherefore tends to be used in a stationary situation. Hence, the memory111 may be allocated such that in a state of portability, the memoryallocation for the buffering of the audio content signal is high, and ina state of stationary use, the memory allocation for the secondapplication may be high. Specifically, the entire available memory maybe allocated to the audio signal presentation when in a portable stateand to the second application when in a stationary state.

Accordingly, the portable audio player 101 comprises a portabilityprocessor 123 which is operable to determine a portability state of theportable audio player 101. The portability processor 123 is connected tothe memory controller 113 which controls the memory allocation of thememory 111 according to the portability state determined. In thepreferred embodiment, the memory allocation may further be in responseto a user input thereby allowing a user to adjust the performance of thedifferent applications. This may be particularly beneficial insituations where the portability processor 123 determines a portabilitystate which is not consistent with the actual current use of theportable audio player 101.

The portability processor 123 may determine the portability stateaccording to any suitable algorithm or criteria. For example, theportable audio player 101 may comprise a movement detector which iscapable of detecting that the portable audio player 101 is being moved.Such a movement detector may for example comprise a small mechanicalvibration sensor, wherein a moveable member forms an electricalconnection if vibrations exceed a given level.

However, in the preferred embodiment, the portability state isdetermined in response to a detection of the portable audio player 101having an external connection. For example, in the described embodiment,the second application requires a connection to an external presentationdevice 121. Thus, if the portable audio player 101 is connected to thesecond presentation device 121, the second application is likely to beused and thus a memory allocation may preferably be provided.Furthermore, the portable audio player 101 is likely to be used in astationary mode as the external presentation device is stationary.Hence, by detecting if the portable audio player 101 is connected to anexternal device 121, the memory allocation of the memory 111 may beoptimised, thereby allowing for increased performance of the differentapplications of the portable audio player 101 and optimising the memoryuse. Accordingly, a reduced total amount of memory is required as theavailable memory is effectively shared. Consequently, the cost of theportable audio player 101 may be reduced and/or the performanceimproved.

The detection of the portable audio player 101 being connected to anexternal presentation device may in the preferred embodiment be bydetection of a signal characteristic of the external device. Forexample, the presence of a voltage on a connector input may be detected,thereby indicating that the external device is connected. Alternativelyor additionally, the detection of the external connection may simply beby a mechanical detection that a connector has been coupled to theportable audio player 101. Thus the portable audio player 101 preferablycomprises a socket for receiving a connecting cable to the presentationdevice 121. The socket includes a mechanical switch, which is triggeredwhen the connecting cable is inserted into the socket. In thisembodiment, the portability processor 123 is operable to set aportability indication to stationary when the mechanical switch istriggered and to portable (non-stationary) otherwise.

As another example, the detection of the portable audio player 101 beingconnected to an external presentation device may be by detection of anexternal load on an output of the device. For example, a monitor may bedetected as an external load on a video connector. The load may forexample be detected by measuring the current drawn from the videooutput.

Alternatively or additionally, the portability processor 123 may beoperable to detect if the portable audio player 101 is connected to anexternal power source. If the portable audio player 101 is connected toan external power source this power source may be a mains adapter thusindicating that the portable audio player 101 is connected to the mainsand consequently operated in a substantially stationary mode. Thedetection may be by detection of a mechanical insertion of a powerconnector in the portable audio player 101 or may be by detection of asignal associated with the external power source. This signal may simplyconsist in the supply voltage or may be an identification signalspecifically indicating that the external power source is asubstantially static power source.

In some embodiments, the second memory allocation provides an improvedperformance of the second application. However, in other embodiments,the second memory allocation is required for the second application tobe performed. Hence, the second application may specifically be designedto rely on the presence of the second memory allocation. Specifically,applications which can only be used in a stationary mode may beimplemented without any additional requirements being put on the memorysize of the device.

FIG. 2 is an illustration of a flowchart of a method of presentingcontent in accordance with an embodiment of the invention. The methodwill be described with reference to the portable audio player 101 ofFIG. 1.

In step 201, the portable audio player 101 receives a first contentsignal from a content source. The content source may be the firstcontent source 103 or may be an external content source. In step 203,which follows step 201, the content signal is buffered in the memory111. Step 203 is followed by step 205, wherein the presentation signalgenerator 105 generates a presentation signal from the first contentsignal. The presentation signal is presented on an external presentationdevice 109. In step 207 the memory controller 113 dynamically adjuststhe buffer memory allocation of the memory 111 for buffering of thecontent signal and of a second memory allocation for a secondapplication. Step 207 is followed by step 209 wherein the secondapplication is processed. The method subsequently repeats in step 201.

The invention can be implemented in any suitable form includinghardware, software, firmware or any combination of these. However,preferably, the invention is implemented as software running on one ormore data processors and/or digital signal processors. The elements andcomponents of an embodiment of the invention may be physically,functionally and logically implemented in any suitable way. Indeed thefunctionality may be implemented in a single unit, in a plurality ofunits or as part of other functional units. As such, the invention maybe implemented in a single unit or may be physically and functionallydistributed between different units and processors.

It will be appreciated that the invention tends to provide one or moreof the following advantages singly or in any permutation or combination:

-   -   It improves performance of and/or enables a plurality of        applications.    -   It reduces memory requirements thus reducing cost.    -   It allows for optimized memory performance for a given        portability state.

These and other advantageous will be apparent from the abovedescription.

Although the present invention has been described in connection with thepreferred embodiment, it is not intended to be limited to the specificform set forth herein. Rather, the scope of the present invention islimited only by the accompanying claims. In the claims, the termcomprising does not exclude the presence of other elements or steps.Furthermore, although individually listed, a plurality of means,elements or method steps may be implemented by e.g. a single unit orprocessor. Additionally, although individual features may be included indifferent claims, these may possibly be advantageously combined, and theinclusion in different claims does not imply that a combination offeatures is no feasible and/or advantageous. In addition, singularreferences do not exclude a plurality. Thus references to “a”, “an”,“first”, “second” etc do not preclude a plurality.

The invention relates to a portable content presentation device (101)such as a portable audio player. The portable presentation device (101)comprises a content signal source (103) for providing a first contentsignal. A memory (111) buffers content signal to provide electronicshock protection. The portable presentation device (101) comprises apresentation signal generator (105) which generates a suitablepresentation signal. The portable presentation device (101) alsocomprises a memory controller (113) which dynamically adjusts the buffermemory allocation and creates a second memory allocation of the memory(111) for a second application. A portability processor (123) determinesa portability state, e.g. indicating stationary or portable use, and thememory allocation is in response thereto, such that the buffer memory isreallocated to the second application, when the portable presentationdevice (101) is used in a stationary mode. The second application may bea second presentation application such as a presentation application forimages.

1. A portable content presentation device comprising: a content signalsource for providing a first content signal; a memory; a presentationsignal generator operable to generate a presentation signal from thefirst content signal; a portability processor for determining aportability state of the portable content presentation device; and amemory controller operable to dynamically adjust a first memoryallocation of the memory associated with the first content signal and tocreate a second memory allocation of the memory for a second applicationin response to the portability state.
 2. A portable content presentationdevice as claimed in claim 1 wherein the first memory allocation is abuffer memory allocation for the first content signal.
 3. A portablecontent presentation device as claimed in claim 2 wherein the firstmemory allocation is electronic shock protection memory and the portablecontent presentation device comprises a shock protection processoroperable to control the buffering of the first content signal in thememory so as to reduce fluctuations in a content signal buffer outputrate.
 4. A portable content presentation device as claimed in claim 1wherein the portability state comprises a portability state indicationof whether the portable content presentation device is in asubstantially stationary state or in a substantially portable state. 5.A portable content presentation device as claimed in claim 4 wherein theportability processor is operable to set the portability stateindication in response to a movement detection.
 6. A portable contentpresentation device as claimed in claim 4 wherein the portabilityprocessor is operable to set the portability state indication inresponse to a detection of the portable content presentation devicehaving an external connection.
 7. A portable content presentation deviceas claimed in claim 6 wherein the external connection is an externalconnection to a substantially stationary presentation device.
 8. Aportable content presentation device as claimed in claim 6 wherein theexternal connection is an external connection to a power source.
 9. Aportable content presentation device as claimed in claim 1 wherein thesecond application is a control application of the portable contentpresentation device.
 10. A portable content presentation device asclaimed in claim 1 wherein the content source is further operable toprovide a second content signal and wherein the second application is aprocessing function associated with the second content signal.
 11. Aportable content presentation device as claimed in claim 1 wherein thesecond application is a presentation application of a second contentsignal.
 12. A portable content presentation device as claimed in claim11 wherein the second content signal is a different type of contentsignal than the first content signal.
 13. A portable contentpresentation device as claimed in claim 12 wherein the first contentsignal is an audio content signal and the second content signal is avisual content signal.
 14. A portable content presentation device asclaimed in claim 13 wherein the second application is an imagepresentation application and the portable content presentation device(101) is operable to use the second memory allocation as an image cache.15. A portable content presentation device as claimed in claim 1 whereinthe second application is enabled by the creation of the second memoryallocation.
 16. A portable content presentation device as claimed inclaim 1 wherein the portable content presentation device is a portableaudio player.
 17. A portable content presentation device as claimed inclaim 1 wherein the memory consists in single memory element.
 18. Amethod of presenting content, the method comprising: receiving a firstcontent signal; determining a portability state of the portable contentpresentation device generating a presentation signal from the firstcontent signal; and dynamically adjusting a first memory allocation ofthe memory associated with the first content signal and a second memoryallocation of the memory for a second application.
 19. A computerprogram enabling the carrying out of a method according to claim
 18. 20.A record carrier comprising a computer program as claimed in claim 19.